Generally, the color of food changes as storage time goes by. The color of food, that is, natural pigment changes according to storage condition or degree of processing, and the change of color is followed by quality deterioration.
Meanwhile, edible pigment is generally used to cooking process of food.
It is advisable to use natural edible pigment but natural pigment is difficult to separate and purify, and the price is mostly high.
Therefore, artificial pigment is generally used to cooking process of food, but harmfulness of artificial pigment to human body is under discussion and it is related to the problem of safety. So detection, separation and purification of natural pigment are important.
Anthocyanin from grape skin is mostly known as natural pigment and 100 g of grape contains about 450˜1,600 mg of anthocyanin.
Anthocyanin pigment has been used for addition agent of confectionery, gum, rice cake or alcoholic liquors and its antioxidant or thrombolytic activity has been known. Meanwhile, cyanidin 3-glucoside from rice cultivar Heugjinju is natural pigment which belongs to anthocyanin group.
This pigment is more stable than the anthocyanin pigment against the change of light, temperature or pH and its extraction method has been disclosed by Korea patent (KR 294731).
The cyanidin 3-glucoside is called “Kuromanin”, which belongs to anthocyanin group.
According to studies, this pigment is superior to free-radical elimination and especially its absorbability of active oxygen which is harmful to human body is so excellent that it can be used for antioxidant system.
It is the purple to black-purple pigment distributed over seed coat and peel of rice. The content of the pigment depends on rice cultivar or percentage of rice kernel. For example, rice cultivar Suwon425 contains 163 mg of cyanidin 3-glucoside per 100 g of seeds, rice cultivar Heugjinju contains 552 mg.
7% of rice kernel contains 15,480 mg of cyanidin 3-glucoside per 100 g of seeds, 14% of rice kernel contains 12,930 mg and 21% of rice kernel contains 6,325 mg. Although there is difference of the pigment content depending on rice cultivar or rice kernel, the present invention provides novel rice cultivar of which pigment content is 4 times as much as the existing rice cultivar Heugjinju.